These are regional variants, bootlegs, hacks, or minor revisions. A clone requires data from the parent ROM to function because it only contains the modified files (such as localized text or altered difficulty settings). ROM Set Configurations
If you update your RetroArch FB Neo core, you may need to update your ROM archive to match the newest DAT (Data Analysis Tool) requirements. How to Set Up an FB Neo ROM Archive
Every single ZIP file is entirely self-contained. The clone archive includes all the parent files it needs.